# Quadcopter or drone robots designing

1. Apr 4, 2015

### rajrocks

Hello everyone !

Its very first post here & with the go i want to know about basic reasons behind the liftup of quadcopters or drone going popular these days.

Is it
the propeller designing
motor weight & speed
battery power
etc ??

2. Apr 4, 2015

### Staff: Mentor

Welcome to the PF.

It helps us a lot if we know what reading and research you've done so far. Can you post links to reading you have done so far, and ask specific technical questions about that reading? Thanks!

3. Apr 5, 2015

### rajrocks

some are making it with soft drink cans & so & so
i saw parrot AR prop.
I got so many things on net but want to know about deep theoritical designings

4. Apr 9, 2015

### Vatsal Sanjay

I have once fabricated (not designed but yet I had to analyse the given blueprint) a qaudrotor. In our design, it is the propeller design and rotation which is responsible for the lift. The lift generated depends on the angular velocity ($\omega$) of propellers. This lift is mainly due to the reaction forces applied by air on propellers when the propellers push air downwards. The $\omega$ of the propellers are set as such that the angular momentum of the system is conserved with respect to it's centre of gravity and your quadrotor is in rotational equilibrium. This results in lifting off of the quadrotor. You simply have to maintain the $\omega$ if you wish to keep your device at a certain height. $\omega$ depend on the configuration of motor and battery employed in your device and this angular velocity (of each propeller) can be varied. (all you need is a transceiver set-up and a little knowledge of coding). Now by varying this $\omega$ you can tilt your quadrotor in desired direction (pitch, roll or yaw) and the movement is taken care of by the reaction forces. For example if you wish to move your quadrotor forward, all you need to do is set the angular velocities such that the quadrotor tilts in forward direction (pitch down) and the reaction forces from air will push your quadrotor forward.

5. Apr 9, 2015

### mheslep

Apropos, today's WSJ has an article and interview with the "father of [copter] drones", explaining the innovations that made the popular
http://www.wsj.com/articles/a-consumer-drone-pioneer-were-learning-as-we-go-1428511868

6. Apr 12, 2015

### CWatters

It's a huge subject covering many different sciences.

To hover the rotor(s) must generate as much lift as the drone weighs. To do that they must accelerate air downwards (F=m*a). They can do that with a large slow rotor or a small high speed rotor. In general large blades are more efficient than small ones which is why real helicopters use relatively few large blades not lots of small ones. Model drones are probably relatively inefficient.

They are popular because they are a lot easier to fly than a conventional model helicopter. Most/many use contra rotating blades so that the pilot doesn't have to deal with the changing torque reaction that a helicopter pilot has to manage.